Fractional line spacer for typewriters



J1me 1931- c. w. CRUMRINE FRACTIONAL LINE SPACER FOR TYPEWRITERS Filed Dec. 13, 1928 w umg l Patented June 2,1031

TES

PATE

NT OFFICE m w. CB'UIBINE, OI BOOHEQTEB, NEW YORK, ASOIG NOB '10 ELEOTBOILTIO mmwmrnna'mc, O1 ROCHESTER, NEW YORK, A CORPORATION OI NEW YORK IRLCTIONAI. LINE SPACER. FOR TYPEWBITEBS Application filed December 13,1838. lcrlal Io. 825,021.

The object of this invention is to produce afractional line spacing construction which shall simple, compact and inexpensive, but convenient and reliable in operation.

To the foregoin end, the invention consists in a constructlon in which a novel form of clutch is employed, the clutch comprising a bo'wed leaf spring, bcarin frictionall at its ends against a cylindrica clutch sur ace, together with means for increasing the curvature ofthe spring, so as to relieve the end pressure, when it is desired to cause-relative rotary movement of the clutch members. In the accompanying drawings, Fig. 1 is a '5 longitudinal section of portions of the platen and-associated parts, in a typewriting machine embodying the present invention. Fig. 2 is a partial longitudinal section, in a plane at a right angle to that of Fig. 1; and Fig. 3 -'is a sectional view, on the line 3-3 in Fig.

1, looking from right to left.

The invention is illustrated as embodied in and associated with a platen 5, of ordinary form, which is mounted, at its ends, in frame members 6 and 7 of the usual carriage. Knobs 8 and 9 are provided for operating the platen in the usual manner, together with a ratchet drum 10, which cooperates with the line-spacing means. These means are not shown, as they may be of any suitable or well known form.

At the right-hand end of the platen is the usual bushing 11, provided with a slotted .bearing 12, to engage the frame member 6 and prevent endwise movement of the platen. The other end of the platen is supported by a bushing 13 of a form peculiar to the present invention. The supporting and controlling rod 14, which passes throughithe' bushings in the usual manner, is provided, near the left-hand end of the platen, with a bearing collar 15 to engage the frame member 7. This collar may be loose upon the rod. The knobs inthe usual manner.

The present invention resides in the particular construction of the clutching means at the left-hand end of the platen, by which the bushing 13 is adjustably connected with the ratchet drum 10. The inner surface of 8 and 9 are fixed upon the ends of the rod 14* the rim of this drum is smoothly cylindrical, and the bushing has a cylindrical flange 16 which fits closely but freely within the drum.

, At diametrically opposite oints the flange 16 is slotted, to receive the on s of a blade spring 17. The length and the normal curvature of this spring are such that it tends to straighten itself from the position shown in Fig. 3, and thus to. press its ends forcibly against the cylindrical clutch surface of the drum 10, so as frictionally to resist rotation of the drum with respect to the bushing 13, and this frictional resistance is suflicicnt to prevent relative rotation of arts during the ordinary operation and t e line-spacing d movements of the platen. At a point adjacent the clutch spring 17 however, the rod 14 has a flattened surface 18, and by rotation of the rod this surface may be brought into engagement with the clutch spring, with the 10 result that the spring is bent to a more curved position, so as to diminish its effective length and thus to relieve the pressure of its ends against the clutch surface.

Inorderthat the knobs 8 and 9 ma be It used to turn the platen through full linespacing angles without disengaging the c utch, the relative rotation of the rod and the bushing 13 is controlled by means comprising a cylindrical member 19, which is 3'0 fastened in the bushing 13 by means of a pin 20. This cylinder 19 hastwo oppositely disposed recesses 21, which are engaged by a' cross-pin 22 on the rod 14. A s rlng 23, interposed between the bushing an the pin 22, holds the arts normally in the positlon shown in the rawings, wherein the pin is in the narrow right-hand ends of the recesses 21. With the parts in this position, relative rotation of the rod 14 and the bushing 13 is positively prevented-thus preventing disengggement of the clutch, so that the knobs may used to rotate the platen and the ratchet drum for full line-spacing movement.

-, When a fractional line-spacing movement 96 is necessary, either of the knobs may be mani ulated to slide the rod 14 from-right to left, thus compressing the spring 23 and bringing the crossin 22 into engagement with the wider leftand portions of the re- I .cesses 21. The rod is then free to be rotated sufiicientl to cause disengagement of the friction c utch, whereu on further rotation of the knobs and the will turn the platen through any desired angle, while the ratchet drum remalns stationary under the influence of the usual line-spacing and retaining means. When the knobs are released the spring 23 forces the rod back to the normal position illustrated, thus causing the crosspin, through its engagement with the camlike surfaces of the recesses 21, to rotate back to a position in which the clutch s ring 17 is released and permitted to lock t eparts frictionally together.

The invention claimed is: Y

1. In a device of the class described, the combination with a cylindrical member and a ratchet wheel connected thereto for stepby-step rotation, of a clutch for releasably connecting the ratchet wheel to the cylindrical member, said clutch comprising an inner cylindrical surface on one of said parts, a bowed blade spring adapted to engage said clutch surface frictionally and retained against rotation relatively to the other part, and externally operable means for increasing the curvature of the spring in a direction transversely to the axis of said cylindrical member to relieve its pressure against the clutch surface.

2. In a device of the class described, the combination with a cylindrical member and a ratchet wheel connected thereto for stepby-step rotation, of a clutch for releasably connecting the ratchet wheel to-the cylindri- '4. In a clutch, the combination of a hollow cylindrical member, an end bushing therein,

a ratchet wheel having an inner c lindrical clutch surface, a flange on said bus ing projectin into said ratchet wheel and having oppos te disposed slots, a bowed blade spring seated in said slots and normally en aging said clutch surface, an axial control ro movable longitudinally in said cylindrical memher a cam surface on said rod cooperative with said blade spring to bend the spring when the rod is manually actuated, a recessed inner projection on the bushing, a pin extending laterally from the control rod into engagement with the recess in said projection to limitrelative rotation of the rod and cylindrical member, and a spring surrounding the rod within said projection and tending to move the rod longitudinally to its normal position disengaged from said blade spring.

CHESTER WM. CRUMRINE.

cal member, said clutch comprisin an inner cylindrical surface on one of sai parts, a bowed blade spring adapted to engage said clutch surface frictionally and retained against rotation relatively to the other part, and an axial supporting rod for the cylindrical member havin an actuating knob at its end and a cam sur ace arranged to engage and bend the sprin to disengage it from the clutch surface and permit rotation of the cylindrical member relatively tothe ratchet 5 wheel.

a In a device of the class described, the

combination with a cylindrical member and a ratchet wheel connected thereto for-step by-step rotation, of a clutch comprising an inner cylindrical clutch surface in said ratchet wheel, and a transversely arranged bowed blade spring adapted to normally engage said surface, means projecting from said cylindrical member into engagement with the ends of said spring to prevent relative rotation between said spring and cylindrical member, a rod mounted axially in said cylindrical member and having relative axial and longitudinal movement therein, a cam on said rod adapted to eng when the rod is turn drical member, and means interposed beand bend the spring relatively to the cylin 

